Copper "Trees"
This is a copper tree from a sample of transformer oil.
Transmitted Off Crossed Circular Polarized Light and Darkfield Reflected Light
Illumination
Definition/Function:
Copper trees will grow on a small fragment of aluminum or iron in transformer oil when
copper is taken into solution in the oil.
Copper will plate the aluminum or iron if only very low levels of copper are present.
These trees that grow very slowly
Significance in the Environment:
This indicates that the oil is corrosive to copper and that some of the copper compounds
formed are soluble in the oil.
Characteristic Features:
The reddish color of the copper stands out in sharp contrast to the white of the
aluminum or grey of iron. Even in low concentrations the copper plating out
on the aluminum or iron will be easily visible.
Associated Particles:
References:
